The mammalian heart beat:
1. Stops when the nerve supply to the heart is cut
2. Originates at AV-node
3. Decreases when stretch receptors in the vena cava are stimulated
4. Slows down when the activity in the vagus nerve increases
 

Subtopic:  Regulation of Cardiac Activity |
 53%
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If a molecule of CO2 released into the blood of a human foetus is exhaled through the mouth of the mother, it will not travel through the:
1. Right atrium of mother
2. Right atrium of foetus
3. Left ventricle of mother
4. Left ventricle of foetus
 
Subtopic:  Human Heart: Double Circulation |
 51%
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If it was possible to genetically engineer humans to be able to run long distances faster at high altitudes, which of the following would not help?
1. Increasing the thickness of cellular lining of the alveoli
2. Decreasing the average size of the alveoli
3. Increasing the amount of Hb in each RBC
4. More than one options as mentioned above 
Subtopic:  Regulation of Cardiac Activity |
 59%
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Assertion (A): RBCs contain a red-colored complex protein called hemoglobin.
Reason (R): RBCs are devoid of nucleus in most of the mammals and are biconcave in shape.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Blood: General Description & RBC |
 88%
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Assertion (A): 'O' group individuals are called universal donors.
Reason (R): Group 'O' blood can be donated to persons with any other blood group.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Blood: Blood Group (A,B,O) |
 86%
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Assertion (A): Nearly 20% of humans have Rh antigens.
Reason (R): Rh antigen is named after Rhesus monkeys.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Blood: Blood Group |
 83%
From NCERT
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Assertion (A): Birds and Mammals have double circulation.
Reason (R): Two separate circulatory pathways are present in birds and mammals where the mixing of oxygenated and deoxygenated blood occurs.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Human Heart: Double Circulation |
 84%
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Assertion (A): ECG is of great clinical significance.
Reason (R): It helps to diagnose possible abnormalities/diseases of the heart.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  ECG & Coronary Artery Disease |
 93%
From NCERT
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Assertion (A): Human heart is myogenic.
Reason (R): Normal activities of the heart are regulated by the human brain.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Regulation of Cardiac Activity |
 70%
From NCERT
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Assertion (A): SAN is called the pacemaker of the heart.
Reason (R): It generates the maximum number of action potentials and hence, it sets the pace of heart beat.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.
Subtopic:  Rhythmic Excitation of Human Heart: Part 1 |
 94%
From NCERT
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